Canadian Policy Wiki:Category
This article is a quick introduction to categories. For detailed technical information on how to use categories, see ' '. For guidelines on creating and organizing categories, see Canadian_Policy_Wiki:Categorization. For answers to frequently asked questions about categories, see Canadian_Policy_Wiki:Categorisation FAQ. Introduction: a message to the new reader A category is a list page which serves to aid browsing of related articles. Categories generally sketch topics rather than define them. Often—but not always—they do classify topics; for example, the category:science is meant to hold individual science topics like biology and geography. If you are new to Wikipedia, and you have just selected the category:science for reading you may have been surprised to have seen two lists: #Subcategories of category:science, such as category:astronomy, and #Articles, such as the Wikipedia article on astronomy. *The first list contains more specialized categories where you can find detailed articles not in the top level category. For example, category:astronomy contains the articles astrophysics and binary stars. There are often multiple levels of categories and subcategories. *When you are interested in a general article, look in the second list (#2 above) for an article title. If you can not find a desired article, it is often in a subcategory. When you are reading an article and want to find the general category to explore, look at the bottom of that article for a "Categories:" box listing all the categories to which the topic of the page belongs. The Categories: links are also on the category pages allowing you to navigate up and down the lists to find the information you need. Example: How to add category links to an article page, and how to assign subcategory links to a category page The next subsections demonstrate the use of the category links using the physics category. How to navigate the category lists To navigate the category lists, you can use the Category TOC links on the category:physics page. Just click on the letter corresponding to the first letter of the article or subcategory which you seek. Alternatively, click on the next 200 or previous 200 links on the category page. How to add categories to the physics articles You can add relevant categories to help populate the subcategory lists. To do this, at the foot of a Physics article (see section below for Physics subcategory), add the text Category:Add physics subcategory here Before saving your edit, to test out the view, you can hit the Preview button to check whether your chosen subcategory is working. By saving your edit, you will produce a link to the physics subcategory. See the source text (click Edit this page above) for an example of the pipe trick, which forces an alphabetization in the category sequence for an item. How to assign physics subcategories to the physics category To add subcategories to the physics category, first view that physics subcategory page via a link from some pertinent physics article in the subcategory. When viewing that physics subcategory page, click Edit this page, and place the text Category:Physics at the foot of the physics subcategory page, above the interwiki links. (The category software currently allocates 200 links per category page, whether they are subcategory or article links.) How to make a physics subcategory sort correctly within the physics category Example: You want subcategory page Category:Physics organizations to be listed on category page Category:Physics. So you add the tag Category:Physics. BUT Physics organizations shows up under "P" for Physics instead of "O" for Organizations. Instead, add the tag Organizations. NOW Physics organizations shows up under "O". That is because of the vertical bar (known often as a pipe) connects the fields in a logical manner; the field after the pipe is used as a sort key. How to link to a category A colon (":'''") before the "category tag", e.g., Category:NameOfCategory, will allow you to include a link to a category page without actually adding the article to that category. By convention, the category tags are placed before the interwiki links, which are usually the very last tags on the article. How to use the Category feature About lists and categories Wikipedia includes a number of lists, but it is difficult to keep these lists complete and up-to-date, and to maintain connections between elements of a list and articles about those elements. Additionally, scaling aspects of the encyclopedia such as browsing, watchlists, and Recent Changes can be improved by identifying the articles with categories. A '''category system has been developed for the MediaWiki software that could automatically generate some of these lists and provide such categorization. The flat list of all categories can be found at , although Category:Fundamental or Canadian_Policy_Wiki:Browse may be more suited for browsing. See also *Canadian_Policy_Wiki:Browse - A navigation page that includes links to high-level categories * - an alphabetical list of all categories with subcategories or categorized articles * *m:Categorization. *Canadian_Policy_Wiki:Category schemes - other tables of contents *Canadian_Policy_Wiki:List, can have more structure and more information within a single page than a category; see also Wikipedia talk:Categorization/Archive 1#Lists v. categories and Category:Lists that should be categories *Canadian_Policy_Wiki:Navigational templates, often a small list for use in several related articles, without the usual disadvantages of duplication; e.g. a county article as well as articles on towns in that county can have the same list of towns; unlike a category, it can also show towns for which there is not yet an article, with a link to conveniently create one; groups of articles can thus be created top-down. *Canadian_Policy_Wiki:What links here - if e.g. a county article does not list the towns in it, this link can help find existing town articles because they are likely to have a link to the county article. * Category Tree browser at the Toolserver; javascript category browser. * Cat Scan Category Category